It promises to be a strange afternoon at Goodison Park today, and not just for David Moyes. As the Scot sends out his Everton team at Goodison for the final time before departing for Manchester United, the supporters could be forgiven for fearing what happens next. After all, it is not just United who have lost their lodestar.

Bill Kenwright, the Everton owner, has lost the manager who delivered the finest football team seen on the blue side of Stanley Park since the Eighties, the bargain-hunter who signed Tim Cahill, Steven Pienaar and Phil Jagielka, the man whose drive and ambition rejuvenated a proud old club – all for an estimated net spend of £16.85 million. Little wonder Kenwright cut an emotional figure when speaking after the decision of Moyes, his friend and ally, to leave for United.

"Distraught" is how Joe Royle, architect of Everton's last trophy win, the 1995 FA Cup, describes Kenwright, and there seems to have been genuine surprise within the club over events this week; although Moyes's contract was ending this summer, he had been planning a pre- season trip to South Africa.

"I think the feeling was David genuinely didn't know what he was going to do at the end of the season," says Royle, although he wonders "how and when David knew" of United's interest. Moyes himself insisted the offer had come "out of the blue" last week, but the succession plan was known among the Old Trafford coaching staff towards the end of last year.

Our source, with close links to Ferguson's backroom team, said he had heard last November that "if United win back the title from Manchester City, Ferguson will see it as the perfect time to go, and Moyes is the man they want".

The revelation underlines the trust Ferguson places in his staff and also the demands he makes of them. They must have known they could become victims of their own success, for any new manager is expected to bring in his own team of coaches.

Moyes and Kenwright were an odd couple – the fastidious, straight-talking Scot and the theatre impresario with luvvie leanings – yet according to Royle, theirs was the "rock-solid" relationship which brought Everton such stability during the last 11 years. "They are great mates. Bill will miss him," says Royle.

The legacy of that partnership is plain to see. Whoever follows in Moyes's footsteps will inherit a squad so much better than that which the sacked Walter Smith bequeathed in March 2002.

Then Everton were embroiled in a relegation fight; now they are on course for a fifth top-six finish in nine seasons. And where there was Bellefield, the charming time-warp of a training ground, now there is the state-of-the-art Finch Farm, where Moyes brought first-team and youth levels together on the same site – Everton are the only Premier League club with teams in both the U18 and U21 national semi-finals – and created a set-up that, to quote one colleague, "took all the excuses away".

Moyes's famed attention to detail is visible there in the dressing-room lockers which display the names of both the players using them and, beneath, their previous occupants. That was part of Moyes's effort to create an "Everton family", and it worked: a recent study placed Everton among the top three most stable squads in Europe's big leagues – nine of the first-team squad have been at the club five years or longer.

The worry for Everton fans is whether Kenwright can maintain the stability of the past decade. Critics of the chairman point to his failure to have attracted any fresh investment in 13 years and, moreover, the unsolved problem of Everton's antiquated, if atmospheric, Goodison home.

Had Kenwright succeeded in his plans to move Everton to a new stadium at Kings Dock, real rather than relative success may have become attainable for Moyes, who did not make a permanent signing of over £1 million between September 2009 and January 2012. He was frustrated again in January this year when looking to strengthen the Premier League's smallest squad.

It is in this context that the Everton Shareholders' Association delivered a petition on Wednesday calling for an emergency general meeting. Kenwright did away with AGMs in 2007 but the shareholders have the requisite number of signatures to force a meeting in June, where questions will be asked about the club's future. To understand their dissatisfaction, it is worth recalling that at the end of Sir Alex's first season at Old Trafford, Everton had the same number of major trophies as United.

Moyes came along and arrested Everton's decline on the field at least, though unlike Harry Catterick and Howard Kendall – the only other men to have overseen over 500 Everton games, and winners of two League titles each – he leaves without a trophy, albeit with much admiration.

Royle will be at Goodison today and anticipates a "warm reception" for the Scot. Assessing his reign, he adds: "He came out with a marvellous phrase about Everton being the 'people's club' and that endeared him straight away. "

Moyes on Friday promised another leaving gift – advice regarding his successor. Evertonians will cross their fingers that he helps Kenwright get that right too.